// XmlElement.h

#ifndef XmlElement_H
#define XmlElement_H

// David Adams
// July 2002
//
// A simple class to hold data describing an XML element.
// An element can hold the following:
//   other elements (managed locally)
//   string attributes
//   a string identifier
//   string identifiers as references to other elements
// All but the first are indexed by name.
//
// This a partial implementation of the XML standard and does
// not provide any capability for parsing or writing files or
// for checking consistency with DTD or style sheets.
//
// Package dataset_xml provides means to read elements from
// or write elements to XML files.

#include <string>
#include <vector>
#include <map>
#include <iosfwd>

class XmlElement {

public:  // typedefs

  typedef std::string String;
  typedef std::vector<const XmlElement*> ElementList;
  typedef std::vector<String> StringList;
  typedef std::map<String, String> AttMap;

private :  // data

  // Error count.
  // Incremented for each error.
  mutable int m_err;
 
  // Name specifying the type of the element.
  String m_name;

  // Identity.
  // Value is "" if undefined.
  String m_id;

  // Child elements.
  ElementList m_eles;

  // References to other elements.
  StringList m_ref_names;
  AttMap m_refs;

  // Attributes.
  StringList m_att_names;
  AttMap m_atts;

  // Parsed character data (text).
  String m_pcdata;

public:  // Constructors, assignment and destructor.

  // Constructor.
  explicit XmlElement(String name ="");

  // Copy.
  XmlElement(const XmlElement& rhs);

  // Assignment.
  XmlElement& operator=(const XmlElement& rhs);

  // Destructor.
  ~XmlElement();

public: // Modifiers

  // All return 0 for success.

  // Set the identity.
  int set_id(String id);

  // Add a child element.
  int add_child(const XmlElement*);

  // Add a reference to another element.
  int add_reference(String name, String ref);

  // Add an attribute.
  int add_attribute(String name, String att);
  int add_attribute_as_bool(String name, bool att);
  int add_attribute_as_int(String name, long att);
  int add_attribute_as_unsigned_int(String name, unsigned long att);

  // Set the parsed character data.
  int set_pcdata(String txt);

public:  // Const methods.

  // Validity.
  // Requires nonblank name.
  bool is_valid() const;

  // Return the error count;
  int error_count() const { return m_err; }

  // Fetch the name.
  String name() const { return m_name; }

  // Fetch the identity.
  String id() const { return m_id; };

  // Fetch the list of children.
  const ElementList& children() const { return m_eles; }

  // Find all children with a specified name.
  ElementList children(String name) const;

  // Return the single child with the specified name.
  // Returns null if there are zero or more than one matches.
  const XmlElement* single_child(String name) const;
  
  // Return the number of children with a given name.
  ElementList::size_type has_children(String name) const;

  // Fetch the references.
  const StringList& reference_names() const { return m_ref_names; }
  bool has_reference(String name) const;
  String reference(String Name) const;

  // Fetch the attributes.
  const StringList& attribute_names() const { return m_att_names; }
  bool has_attribute(String name) const;
  String attribute(String name) const;
  bool attribute_as_bool(String name) const;
  long attribute_as_int(String name) const;
  unsigned long attribute_as_unsigned_int(String name) const;

  // Fetch the parsed character data (text).
  String pcdata() const;

  // Write to xml text.
  // If indent = "NOCR", then there is no formattiong with indents
  // or carriage returns.
  std::string to_xml_text(std::string indent ="") const;

  // Size of managed memory in bytes.
  size_t memsize() const;

};

// Output stream.
std::ostream& operator<<(std::ostream& lhs, const XmlElement& rhs);

#endif